A Process for Producing Hydrogen and Graphitic Carbon from Hydrocarbons

Abstract

In accordance with the present invention, there is provided a process for producing hydrogen and graphitic carbon from a hydrocarbon gas comprising: contacting at a temperature between 600° C. and 1000° C. the catalyst with the hydrocarbon gas to catalytically convert at least a portion of the hydrocarbon gas to hydrogen and graphitic carbon, wherein the catalyst is a low grade iron oxide.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a process for producing hydrogen and graphitic carbon.BACKGROUND ART[0002]Hydrogen has many commercial uses, such as a clean and environmentally friendly alternative to fuel in internal combustion engines. Carbon, or more particularly graphite, is considered a key material in the emerging green technology market. It has been shown to be useful in energy storage, electrical conduction devices, catalyst supports, lubrication additives and modern electronics equipment. All references to carbon within this patent relates to the graphitic form of carbon, therefore these terms are used interchangeably throughout.[0003]Conventional methods of producing hydrogen from fossil fuels however produce carbon dioxide (natural gas steam reforming and coal gasification) which is harmful to the environment.[0004]Natural gas can be catalytically cracked into both hydrogen gas and solid carbon according to Equation (1).CH4→C+2H2   (1)[0005]In...

AI Technical Summary

Benefits of technology

[0056]In a second form of the present invention where multiple reactors are used in a series which allows catalyst flow between reactors, unreacted hydrocarbon gas is provided to each reactor. In this arrangement, hydrocarbon gas is continuously flowed through the reactor. Unreacted catalyst is provided in the lowest pressure reactor, which following the catalytic conversion of the methane, produces a partially deactivated catalyst. The partially deactivated catalyst is transferred into the next reactor of higher pressure in the series for further catalytic conversion of methane. The higher pressure of the reactor allows for further deactivation of the catalyst. The transfer of the partially deactivated catalyst repeats along multiple reactors of increasing pressure. When unreacted hydrocarbon gas is provided in each reactor, the applicant has termed this arrangement a parallel catalyst multiple pressure reactor (parallel catalyst MPR).

[0057]In a third form of the present invention the multiple reactors are arranged in a series which allows for both the hydrocarbon gas and catalyst to flow between reactors in opposite directions. In this arrangement, unreacted catalyst is provided in the lowest pressure reactor and unreacted hydrocarbon gas is provided in the highest pressure reactor. The catalyst is transferred between the chambers of increasing pressure counter-currently to the gas flow between the chambers. The applicant has termed this arrangement a counter-current multiple pressure reactor (counter-current MPR). The partially deactivated catalyst retains activity in the higher pressure reactors, and the resultant graphite product has higher purity (as % of mass) with correspondingly higher value.

[0058]The inventors have found that the counter-current MPR arrangement allows for more complete conversion of the hydrocarbon gas and a higher purity graphitic carbon product. As there is no catalyst flow in parallel gas MPRs or no gas flow in parallel catalyst MPRs, the design is much simpler than the counter-current MPR.

Problems solved by technology

Conventional methods of producing hydrogen from fossil fuels however produce carbon dioxide (natural gas steam reforming and coal gasification) which is harmful to the environment.

Whilst the above process is known, it has not been exploited commercially for a number of economic reasons.

This primarily relates to the underlying catalyst costs, both in the initial supply, as well as costs in recycling and regenerating the catalyst.

The vast majority of researchers in this area have utilised expensive and complex supported catalysts which, despite their high catalyst activity and product yield, result in extremely high catalyst turnover costs.

These costs are a significant barrier to commercialising the use of such catalysts.

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